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Genetics > M1 L2: Mitosis and Meiosis > Flashcards

M1 L2: Mitosis and Meiosis Flashcards

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Biology 101 flashcards
1
Q

what is genetic continuity

A

the process of passing genetic material onto future generations so that the offspring resemble the parents

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2
Q

what’s the role of the plasma membrane? what cells have one?

A

separates the inside of the cell from the environment. all cells

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3
Q

what’s the role of the cell wall? what cells have one?

A

provide more structural support. plant cells

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4
Q

what’s the role of the glycocalyx? what cells have one?

A

outer layer of glycoproteins and polysaccharides that acts as the cell’s ID. many animal cells

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5
Q

What is the cytoplasm? what does it contain?

A

everything outside the nucleus, contains organelles and cytosol (liquid that also contains free ribosomes), structures that make up the cytoskeleton (microtubules from tubulin, microfilaments from actin)

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6
Q

what are the two parts of the ER? what does each do?

A

rough has ribosomes on the surface, site of translation and protein synthesis

smooth does not have ribosomes, site of phospholipid and fatty acid synthesis

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7
Q

what’s the role of mitochondria? what’s special about this organelle?

A

site of oxidative phosphorylation and ATP synthesis

they have their own DNA (mtDNA), replicate themselves, transcribe and translate their own proteins, result of endosymbiosis

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8
Q

what’s the role of chloroplasts? what’s special about this organelle?

A

capture sunlight for photosynthesis

have their own DNA (cpDNA), replicate themselves, transcribe and translate their own proteins, result of endosymbiosis

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9
Q

Characteristics of prokaryotes

A

chromosome is in nucleoid region, no nucleus, no membrane bound organelles, DNA less compacted and less associated with proteins, circular chromosomes

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10
Q

Characteristics of eukaryotes

A

nucleus, membrane bound organelles, DNA more compacted and more associated with proteins, linear chromosomes

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11
Q

whats the nucleolus

A

inside nucleus, where rRNA is made, ribosome assembly starts

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12
Q

what parts of DNA contain repeats of rRNA genes?

A

nucleolar organizer region (NOR)

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13
Q

what’s chromatin

A

fibers of DNA and proteins that make up chromosomes

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14
Q

what’s the centromere?

A

constricted part of chromosome, specialized sequence where kinetochore binds, divides chromosome into p and q arms, allows us to qualify chromosomes in categories

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15
Q

categories of chromosomes / centromere locations

A

1) metacentric: centromere in middle
2) submetacentric: near middle
3) acrocentric: near end
4) telocentric: at end

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16
Q

what are homologous pairs

A

pairs of chromosomes with the same genes, possible different alleles

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17
Q

what’s biparental inheritance?

A

offspring get one chromosome from each parent

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18
Q

dwhat’s the difference between sister chromatics and homologous pairs?

A

sister chromatids are the product of DNA replication, identical

homologs are the same chromosome but from different parents, same genes but might not have identical alleles

19
Q

does chromosome number correlate with genome size or complexity? how do we know?

A

NO. fruit flies have 4 chromosomes, yeast has 16

20
Q

what is karyokinesis?

A

separation of genetic material into daughter cells

21
Q

what’s cytokinesis?

A

separation of organelles and membranes into daughter cells

22
Q

Purpose of mitosis?

A

asexual reproduction in budding organisms, growth from zygote to adult for multicellular organisms

23
Q

what are the phases of the cell cycle

A

interphase (G1/G0, S, G2) and mitosis (prophase, prometaphase, metaphase, anaphase, telophase)

24
Q

describe the subphases of interpahse. are chromosomes visible?

A

G1- cell grows, may go into G0 (nondividing but metabolically active)

S- cell replicates DNA

G2- cell grows, prepares for mitosis

CHROMOSOMES NOT VISIBLE

25
Q

describe mitosis prophase

A

centrioles (organelles made of tubulin) go to centrosomes on opposite ends of cell most plants/fungi don’t have centrioles

nuclear envelope breaks down

chromosomes condense, form sister chromatids (sister arms held together with cohesin)

26
Q

describe mitosis prometaphase

A

centrioles reach opposite poles, produce spindle fibers from centrosome

kinetochore binds centromere (# kinetochore attachments/chromosome varies across organisms)

spindle fibers attach to kinetochore

separase degrades cohesin except at centromere (shugoshin protects cohesin)

sister chromatids migrate to metaphase plate

27
Q

what are spindle fibers made of? what are their 3 functions?

A

microtubules made of tubulin.

1) chromosome movement
2) stabilize cell during division
3) cell elongation before cytokinesis

28
Q

describe mitosis metaphase

A

chromosomes are lined up on metaphase plate

29
Q

describe mitosis anaphase

A

sister chromatid disjunction into daughter chromosomes via molecular motor proteins (use ATP to shorten spindle fibers)

shugoshin and cohesin break down

30
Q

describe mitosis telophase

A

full set of chromosomes on each end of cell

cytokinesis (animal cells: form cell furrow by constricting cell membrane along metaphse plate) (plant cells: cell plate forms, site of new cell wall)

reform nuclear envelope

decondense chromosomes

31
Q

what proteins regulate the cell cycle

A

cyclins are produced at different points in the cell cycle

cyclins bind to and activate cyclin dependent kinases

CDKs phosphorylate other proteins

32
Q

what are the 3 checkpoints in the cell cycle

A

G1/S - big enough to replicate DNA? DNA damage?

G2/M - DNA replication finished? Replicated correctly?

M- spindle fibers formed and fully attached to kinetochores?

33
Q

can haploids and diploids sporulate?

A

sporulation = meiosis, only diploids can, both can do asexual reproduction with mitosis

34
Q

purpose of meiosis?

A

go from 2N to N to maintain genetic continuity (not make a 4N zygote)

35
Q

what’s crossing over?

A

homologs exchanging genetic material in meiosis I

36
Q

how to tell when ploidy has been reduced?

A

count centromeres

37
Q

describe the 5 steps of prophase I

A

chromosomes already replicated

1) leptonema: chromatin condenses (chromomeres: localized condensations resemble beads), chromosomes become visible, start looking for homolog

2) zygonema: synaptonemal protein complex forms between homologs, closely associated homologs = a bivalent

3) pachynema: homologs get closer (synapsis), crossing over, double structure of each homolog in the bivalent is clear = a tetrad

4) diplonema: homologs separate slightly, still joined at chiasmata (site of recombination)

5) diakinesis: terminalization (chiasmata move to ends of chromosomes), nucleolus and nuclear envelope break down, spindle fibers attach to kinetochores on homolog centromeres

38
Q

how do X and Y chromosomes pair?

A

have pseudoautosomal regions (PAR)

39
Q

describe the rest of meiosis I. What are the analogous structures in mitosis?

A

metaphase I: recombined tetrads (pair of homologs) line up on metaphase plate (homologs are side by side but would be end to end in mitosis)

anaphase I: recombined homologs are pulled apart (disjunction) (would be sister chromatids in mitosis), form dyads

telophase I: cytokinesis, separate into 2 daughter cells, sometimes form nuclear envelope

prophase II: dyads (nonsister chromatids) still condensed

metaphase II: dyads line up end to end

anaphase II: nonsister chromatids of dyads get pulled apart

telophase II: cytokinesis, nuclear envelope forms

40
Q

molecular basis for independent assortment?

A

SBS arrangement of bivalents in tetrads is random in metaphase I

41
Q

minimum possible genetic combinations 2 organisms can produce in their offspring?

A

(2^n)^2

2 (maternal/paternal allele) ^n (for # of unique chromosomes) ^2 (both parents contribute)

42
Q

describe meiosis in males

A

spermatogenesis: diploid spermatagonium grows into primary spermatocyte, meiosis I makes 2 secondary spermatocytes, meiosis II makes 4 spermatids, gain mobility and become mature spermatozoa

*cytoplasm divides equally

43
Q

describe meiosis in females

A

oogenesis: diploid oogonium grows into primary oocyte, meiosis I makes a secondary oocyte and polar body, meiosis II makes an ootid and another polar body, grows into ovum

*cytoplasm does not divide equally

44
Q

are all genes DNA?

A

no, some viruses use RNA as genetic material. everything else uses DNA

Genetics (7 decks)

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